1. Field of the Invention
This invention relates generally to electroplating apparatus and more particularly to a novel drum-type electroplating apparatus for relatively large parts, such as large fasteners and the like.
2. Prior Art
Heretofore, it has been common practice to batch electroplate relatively small parts, such as small fasteners and the like, using rotary drum-type electroplating apparatus. A typical electroplating apparatus of this kind has a plating drum which rotates in an electroplating solution and contains one or more plating chambers for receiving a batch of parts to be plated. The walls of each plating chamber contain openings through which plating solution enters the chamber. Each plating chamber contains at least one of the plating electrodes for contact with the parts in the chamber. The other plating electrode is located either within the chamber or within the plating solution tank, whereby during operation of the plating apparatus, the parts in each drum chamber are electroplated. Examples of such electroplating drums are found in U.S. Pat. Nos. 639,766; 2,865,831; 3,582,526; 3,650,937; 3,850,727; and Great Britain Patent No. 1,204,902.
While a drum type electroplating apparatus of the kind discussed above is suitable for relatively small parts, such as small fasteners and the like, it is not suitable for relatively large parts, such as large bolts and other fasteners, for the reason that during rotation of the plating drum, the loose parts in the drum roll about in the drum chambers and thus constantly impact one another. This impact of the parts presents no problems when the parts are relatively small. On the other hand, when the parts are relatively large, such as large fasteners and the like, such impact of the parts with one another tends to damage the parts, such as the threads of bolts, and mars the electroplated surfaces of the parts. Accordingly, a need exists for a drum type electroplating apparatus for relatively large fasteners and other parts which is not subject to this type of part damage. A search of the prior art in this regard developed the following U.S. Pat. Nos.: 560,931, 1,367,567, 3,491,013 745,378, 2,071,261, 3,607,703, 923,319, 2,079,037, 1,353,194, 3,058,902.